Kelly Ripa was visibly saddened when co-host
Regis Philbin announced
his upcoming retirement from the show during the Jan. 18 broadcast -- but if rumors are to be believed, her composure is even more impressive.

TMZ, through whatever odd means they seem to come up with this stuff,
reports that Philbin broke the news to Ripa a mere 15 minutes before air time.

Ripa is apparently "stunned" but "not upset" -- and the source they're citing says the last-minute reveal wasn't personal. He just didn't want the news to leak early.